1. Technical Field of the Invention
The present invention relates to a moving picture coding apparatus and a TV phone using the same.
2. Description of the Prior Art
Handwritten images are often transmitted in TV conferences and TV telephones. FIG. 5 is a block diagram of a transmitting system of a TV phone with an input for handwritten images, while FIG. 6 is a block diagram of receiving system of a TV phone with an output for handwritten images.
Voice signals from microphone 10, moving pictures from camera 12 and handwritten images pen input 14 are coded by voice coding circuit 11, moving picture coding circuit 13 and data coding circuit, respectively. These coded data are multiplexed by multiplexer 16 which is connected with a transmission channel.
The multiplexed data is demultiplexed by demultiplexer 17. Then, the voice signals are decoded by voice decoding circuit 18 and outputted to speaker 19, the moving pictures are decoded by moving picture decoding circuit 20 and outputted to moving picture monitor 21, and the handwritten data are decoded by data decoding circuit 22 and outputted to handwritten image monitor 23.
Both the transmitting and receiving system in the TV phone should share a data transmission protocol.
A moving picture signal may be combined with a handwritten image signal and decoded by moving picture coding means, as disclosed in JP 11-234639 A (1999). FIG. 7 is a block diagram of a transmitting system of a TV phone. A moving picture from camera 12 and a handwritten image from pen input 14 are combined by combining circuit 31 into a combined image 33 which is coded by moving picture coding circuit 32.
FIG. 8 is an example of image 42 by combining a moving picture 40 with a handwritten image 41 of which image size is adjusted.
However, it requires unnecessarily much calculations and electric power to code, by conventional method of coding moving pictures, the handwritten image almost all of which regions are still.
An object of the present invention is to code the handwritten image with less quantity of calculations and less electric power consumption in moving picture coding apparatus and TV phone using the same.
The moving picture coding apparatus of the present invention comprises a combining circuit for combining a moving picture with a handwritten image, a motion compensative moving picture coding circuit for coding all the moving picture and a newly added part in the handwritten image.
The motion compensative moving picture coding circuit codes only the newly inputted region, on the basis of information concerning a region already coded and a region newly inputted. According to the present invention, a quantity of calculation and power consumption of moving picture coding apparatus and TV phone using the same can be reduced, by coding only the newly inputted handwritten image.
Degradation of image quality can be further reduced by putting its motion vector xe2x80x9c0xe2x80x9d.